1 Nisan 2017 Cumartesi

Finnish Soldiers Listening Aircrafts with Acoustic Locator

 Listening aircraft with a huge acoustic locator

Finland had three major battles during World War II. The first two were against the Soviet Union. The last battle was against Germany, which was allied.

The Finnish soldiers were using acoustic locator to find the soviets aircrafts.

Acoustic location is the science of using sound to determine the distance and direction of its source or reflector. Location can be done actively or passively, and can take place in gases (such as the atmosphere), liquids (such as water), and in solids (such as in the earth).

As World War II neared, radar began to become a credible alternative to the sound location of aircraft. For typical aircraft speeds of that time, sound location only gave a few minutes of warning. The acoustic location stations were left in operation as a backup to radar, as exemplified during the Battle of Britain. Today, the abandoned sites are still in existence and are readily accessible.
After World War II, sound ranging played no further role in anti-aircraft operations ( source wiki )

They looking out toward approaching aircraft with binoculars and listening with a huge acoustic locator.